Air-conditioning systems for vehicles, configured to operate in both a cooling system mode and a heat pump mode for heating, cooling, and dehumidifying air which will be supplied to a passenger compartment and be conditioned therein, are known in the related art. Such air conditioners are controlled at the refrigerant circulation system side or air side thereof.
Conventional air side-controlled compact air-conditioning systems having heat pump functions include a structurally simple refrigerant circulation system which has an evaporator, a compressor, a condenser/gas cooler, and an expansion member. In this case, the evaporator is operated as an evaporator in both a cooling system mode and a heat pump mode, and the condenser is also operated as a condenser in both the cooling system mode and the heat pump mode. In this regard, heat flows are completely controlled through air-side flow control. Heating, cooling, and dehumidification functions allow air, which will be supplied to a passenger compartment, to be provided at any mixing temperature by interconnecting the air sides of air-conditioning systems so as to be suitable for the purpose. In this case, the air flow, which excessively flows in the condenser, as a hot-air flow may be mixed, as needed, with the air flow, which excessively flows in the evaporator, as a cold-air flow, so as to be adapted for a required blowing air temperature. The mixed air flow is guided to the passenger compartment through flow channels. The air flow is guided to corresponding discharge ports, such as at least one discharge port on a front window, in-dashboard discharge ports for directly blowing air to occupants, and discharge ports for blowing air to legroom, by an air distribution system which has various discharge control members and is disposed in the vehicle. Excess air is discharged to the outside through additional discharge ports from the housing of the compact air-conditioning system.
FR 2 743 027 A1 discloses an air conditioner for vehicles, which includes a conventional refrigerant circulation system having only an evaporator, a compressor, a condenser, and an expansion member. Heat exchangers are disposed within separate flow channels in the form of at least fluid separation. The flow channels have cross connections or bypasses. The air mass flows introduced by blowers are guided by the closing and opening of flaps and via the surfaces of the heat exchangers by passing through the bypasses according to operating modes if necessary. In this case, the air mass flows are cooled and/or dehumidified or heated, and are then discharged to a passenger compartment and/or to the outside.
DE 10 2011 052 752 A1 discloses a modular air conditioner for vehicles, which has a heat pump function for heating and cooling air. The air conditioner for vehicles includes a housing, which has a blower and flaps for adjusting air flow paths, and a refrigerant circulation system which has a condenser, an evaporator, an expansion member, and associated connection lines. An evaporator-air flow path with an integrated evaporator and a condenser-air flow path with an integrated condenser are formed in the housing. The two air flow paths are connected to each other through the controllable flaps such that a passenger compartment is heated and cooled only through the adjustment of the air flow paths.
DE 10 2012 108 891 A1 discloses an air-conditioning system for conditioning air in a passenger compartment. The air-conditioning system includes a housing having first and second flow channels for guiding air, and a refrigerant circulation system having an evaporator and a condenser. The evaporator is disposed in the first flow channel, and the condenser is disposed in the second flow channel. In this case, at least one heat exchanger, i.e. the evaporator or the condenser, from among the heat exchangers, is configured such that a portion of the heat transfer surface thereof is disposed in both the first flow channel and the second flow channel. The ratio of the heat transfer surface required for each operating mode may be adjusted in such a manner that air is supplied to the heat transfer surface by air guide devices.
The air-conditioning systems known in the related art are characterized in that air guided to the passenger compartment is mixed from various air flows to have a mixing temperature. As a result, air having a uniform temperature is supplied to the air distribution system disposed in the vehicle, and the flows of air introduced to the passenger compartment from all of the opened discharge ports is discharged at the same temperature. However, requirements for formation and operation of the air-conditioning systems are present in the vehicles. According to the requirements for formation and operation of the air-conditioning systems, in order to accomplish the temperature stratification of pleasant air so as to correspond to warm legroom (lower region) and a cold head region (upper region), air discharged from the discharge port of the dashboard for directly blowing air to occupants should be colder than air introduced into the legroom from the discharge port (thereof). Therefore, the temperatures of air flows discharged from individual discharge ports, in particular discharge ports which are provided in the dashboard and communicate with the legroom, may be individually adjusted. However, the individual temperature adjustment may not be realized by the flow rate of air discharged from all of discharge ports having a uniform temperature.